1. Field of the Invention
The present invention relates to vehicle shifting mechanisms, and more particularly, to a vehicle shifting mechanism for actuation of a clutch and gear-shifting of a shift drum in a transmission.
2. Description of the Prior Art
As regards vehicles equipped with an automatic manual transmission (AMT) mechanism, gear-shifting takes place in a transmission while engagement and disengagement of a clutch is under the control of an automatic clutch actuator and rotation of a shift drum is under the control of an automatic gear-shifting actuator. The clutch and the shift drum are each driven by an actuator and a motor. However, the conventional AMT mechanism comprising two or more actuators and motors is disadvantaged by limited room and high costs.
To overcome the aforesaid drawbacks, transmission manufacturers put forth an AMT mechanism designed for automatic transmission vehicles (ATV) and characterized by space saving and low costs. The AMT mechanism comprises a single motor such that actuation of a clutch and gear-shifting of a shift drum in a transmission is powered by the motor operated at a forward/reverse mode. Gear-shifting takes place in the situation where the motor is linked to a shift drum by claws and resilient springs. Actuation of a clutch takes place in the situation where a rocker arm connected to the claws is linked to a cam.
Although the aforesaid single-motor solution solves the space-related and cost-related drawbacks of a conventional double-motor transmission, the single motor is required to rotate in two directions, forward rotation and reverse rotation, in order to shift one gear, thereby delaying consecutive gear-shifting.
The rocker arm is linked to the clutch cam only when spring resilience is restored by the claws. As a result, unsatisfactory linearity of the clutch actuating is inevitable. With power being transmitted via the rocker arm, accumulative precision between the motor and the cam deteriorates.
Driven by means of the claws, the shift drum cannot be driven anew unless the shift drum is reinstated by means of a spring. Hence, consecutive gear-shifting may be delayed due to slow spring resilience.
Accordingly, an issue calling for urgent solution involves overcoming the aforesaid drawbacks of the prior art.